This invention relates to dispensers for particulate material, having particular utility for use with materials which agglomerate when subjected to shearing or compressive forces.
For the past several centuries, it has been known that moist forage, such as green corn or hay, could be preserved in a succulent state by the exclusion of air, whereby the forage undergoes various chemical changes. In this method of preservation, moist fodder is stored in a silo, fermentation occurring and the crop temperature rising until all the air in the interstices of the silage is exhausted. Even after chopping, the plant cells of fresh green crops continue to take in oxygen from the air and to give off carbon dioxide which replaces the oxygen in the air. During fermentation, anaerobic bacteria convert the sugars, starches, etc. into lactic, acetic, and other acids.
Crops with a low content of protein and calcium, such as corn, sorghums, and small cereal grains, will develop enough acid to make them good silage. Crops with a high content of protein and calcium, such as the legumes or immature grasses, should have molasses or acid added. Although silage is an easy form in which to feed forage to livestock, most silage has a low mineral and protein content, and is not suitable for use as a ration. It has been conventional for many years to supplement silage by adding molasses at the time the chopped forage is transported to the silo for storage. The process may involve the periodic addition of liquid molasses after a certain amount of silage has been stored, but it is both difficult and imprecise. There does not seem to be any particularly good way of dispensing liquid molasses to silage, because slight changes in viscosity affect the rate of dispensing, and nozzles have a decided tendency to become clogged wih sticky materials, often further complicated by the inclusion of dust.
A recent development provides for absorbing liquid molasses into diatomaceous earth, forming small free-flowing particles up to about 300 mils in diameter, the product having a bulk density of about 40 lbs./ft..sup.3. This product and the method of making it are described in U.S. Pat. No. 3,859,448. Such particles would seem to lend themselves to being dispensed somewhat more controllably than liquid molasses. Unfortunately, however, the nature of the individual particles of so-called "encapsulated molasses" is such that conventional methods of handling particulate material are not satisfactory. For example, a dispensing hopper having an attached vibrator (a device often employed with dry particulate material) literally shakes the molasses out of the capsules. Similarly, an auger develops a shearing or compression action which expresses the molasses from the original dry particles and gums up the equipment. Attempting to meter the particles through sieve-like plates is similarly ineffective. The same type of result occurs if an attempt is made to dispense the particles through a mechanism such as that employed in a lawn fertilizer spreader. In fact, any dispensing technique based on the use of a paddle wheel which passes closely adjacent to another surface has tended to break down such particles.
Encapsulated molasses can be blended with selected powder amino acids, trace elements, and other additives to provide a "pro-biotic" supplement suited for any given type of forage to promote said rapid fermentation and optimize the food value of the resultant silage. Because the specific additives are tailored to the nature of the forage, while the molasses remains constant, it is considered practical to simply add the requisite powdered elements to the pre-encapsulated molasses and dispense the mixture. Thus, it is not practical to employ a peripherally corrugated roll, since the corrugations tend to cause particles and powders to be classified into different sizes, the powders being dispensed first and rendering the composition of the dispensed supplement inconsistent.
In short, prior to the present invention, there has not been a commercially acceptable method of dispensing "encapsulated molasses" into silage.